In general, voltage readings on input pins of controller may experience noise produced by an alternating current (AC) voltage signal on another input pin of the controller. An AC signal coupled to an analog to digital (A/D) input pin of the controller may generate noise on the signals coupled to other A/D input pins of the controller. In some systems, the noise on other input pins may be particularly noticeable when the magnitude of the AC voltage signal on the A/D input pin is much larger than the positive supply voltage (VDD) for the controller the voltage readings for the other pins become skewed. As a result of the generated noise, the signal on the other pins sampled by the controller may be inaccurate, potentially causing the controller to execute the wrong instruction as a function of the erroneous input. For example, the instruction may be related to voltage magnitude, and the reported voltage is compared to values in a look-up table corresponding to a particular instruction.
Some known systems add filters and/or other additional hardware to a control circuit to attempt to limit the noise problem produced by a AC signal on an A/D input pin. Such additions add to the cost of the control circuit.
This Background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.